docs: Document automatic builds path inclusion

Author: jcowhigjr

CHANGELOG.md

@@ -1,5 +1,11 @@
 # `tailwindcss-rails` Changelog
 
+## Unreleased
+
+### Added
+
+* Added default `app/assets/builds` path to Rails asset paths in the engine initializer. This ensures generated CSS in builds folder is served without manual configuration.
+
 ## v4.2.3 / 2025-05-02
 
 ### Improved

README.md

@@ -30,6 +30,7 @@
   * [Class names must be spelled out](#class-names-must-be-spelled-out)
   * [`ERROR: Cannot find the tailwindcss executable` for supported platform](#error-cannot-find-the-tailwindcss-executable-for-supported-platform)
   * [Using asset-pipeline assets](#using-asset-pipeline-assets)
+  * [Asset path configuration with Propshaft](#asset-path-configuration-with-propshaft)
 - [License](#license)
 
 <!-- tocstop -->
@@ -484,6 +485,12 @@ The inline version also works:
 <section class="bg-[url('image.svg')]">Has the image as it's background</section>
 ```
 
+### Asset path configuration with Propshaft
+
+When using Propshaft as your asset pipeline, the gem automatically adds `app/assets/builds` to your Rails asset paths. This ensures that Tailwind CSS output files are served correctly without requiring manual configuration in your application.
+
+If you're manually configuring asset paths with Propshaft, be aware that this is handled for you by the gem's engine initializer.
+
 ## License
 
 Tailwind for Rails is released under the [MIT License](https://opensource.org/licenses/MIT).